Fig. 2.

ALES is composed of basaloid cells with round to oval nuclei and minimal cytoplasm (a, 20x). A subset of tumors demonstrates rosette formation (b, 20x), peripheral palisading, and keratin pearl formation (c, 20x), with rare production of basement-membrane-like matrix (d, 20x). Tumor cells are uniform and monotonous despite conspicuous necrosis (e, 20x) and an elevated mitotic rate (F, 20x)